Liquid-tight boat-shaped packaging tray and its manufacturing method

ABSTRACT

Fluid-tight, boat-shaped packaging tray comprises a bottom surrounded by sides, connected in pairs by means of inwardly backfolded bellows. These bellows comprise two portions which contact one of the sides. The first portion of the bellows, adjacent to the side contacting the bellows, has an upper cut-out portion which provides for direct contact between the second portion of the bellows and the side of the packaging tray which contacts the bellows during fabrication. The fabrication provides a method whereby simple gluing of the internal faces of the sides intended to contact the bellows allows the front face of one of the portions to be assembled with the back face of the other portion in order to facilitate erection and assembly of container and to maintain the fluid-tight nature of the corner. This assembly method requires the application of adhesive to only one side of the cardboard blank from which the packaging tray is formed, and the resultant structure prevents liquid from rising by capillary action and provides an attractive external appearance of the packaging tray.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to the field of packaging and concerns moreparticularly a liquid-tight cardboard tray produced from a suitablecardboard blank and the process by which the blank is assembled.

2. Description of Related Art

Some food products, such as the meat of poultry, steak or liver, areusually packed in packaging in the form of trays associated with aprotective plastic film.

These trays are generally made from a polystyrene type material, andalthough relatively cheap to produce, they do have the drawback of notbeing biodegradable or recyclable.

To overcome these drawbacks, cardboard trays have been suggestedcomprising a bottom that is generally rectangular and comprises foursides. Sealing at the corners is ensured by bellows which are foldedback against one of the lateral walls and held in position by gluing.

These bellows are produced in two generally triangular portions. Tomaintain the volume of the tray, one of these portions is glued on theback and the other on the front, depending on whether they arepositioned inside or outside of the tray.

This double application of glue complicates automatic assembly of thetrays, the complexity involved calling for the use of bulky assemblymachines and limiting the speed at which the trays can be assembled.

A liquid-tight cardboard container is described in document U.S. Pat.No. 1,959,613. Its corners are provided with bellows in two portions,one of which comprises an opening or cut-out allowing the other portionof the bellows to come into direct contact with the receiving side.Thanks to this feature, the volume of the packaging can be maintained byapplying glue to only one side of the cardboard blank.

In this container, the bellows are folded back against the outside toavoid the presence of internal folds and to keep the cut edges of theblank that are likely to absorb liquid outside the internal volume.Given the leak-proof end use of this container, for packaging liquidsfor example, it is indispensable for the bellows to be positioned on theoutside.

However, in relation to the assembly process of the packaging,particularly the application of glue to only one face of the blank, thisstructure cannot prevent liquid from seeping between the two portions ofthe bellows. Liquid is also able to rise up by capillary action and passquickly into the heart of the cardboard via the upper cut edge, thuscausing the component material to break, the packaging to sag and itscontents to drain away. The presence of external bellows also makes thistype of packaging unattractive.

Document U.S. Pat. No. 4,304,352 describes a similar structure in whichthe drawbacks of the above-mentioned container, particularly liquidseepage between the two portions of the bellows and the rising of saidliquid by capillary action, are overcome by providing for recto-versogluing.

In this leak-proof container, intended for packaging liquid orsemi-liquid products, the upper cut-out provided in one of the portionsof the bellows allows the other portion of the bellows to be glued on tothe reception side in order to improve the strength of the corners. Italso facilitates the assembly of the corners, in conjunction with thepresence of an edge to receive a sealed cover.

In view of the intended use of this container, and for the reasonsexplained above in connection with document U.S. Pat. No. 1,959,613, itscorner bellows have to be folded back against the outside of thecontainer, Such a structure is not very attractive and limits thepossibilities of applying exterior markings.

In addition, the recto-verso gluing of bellows makes for a particularlycomplicated assembly installation. The leak-proof containers describedin documents U.S. Pat. Nos. 1,995,613 and 4,304,352 have very specificend uses that are different from those that are the object of thepresent invention. They are in fact adapted to packaging liquid productsand must be associated with an occultation system in the form of a coverto retain the packaged product.

SUMMARY OF THE INVENTION

The cardboard tray that is the object of this invention is intended forthe packaging of food products of the types such as chicken breast,steak or any other food products likely to exude small amounts ofliquid. The object of this tray is to contain these small amounts ofliquid, and it therefore comprises sealing properties, particularly atthe corners of the bottom, adapted to stop liquid rising by capillaryaction. It is also very simple to produce and can be assembled byautomatic means at very high speeds.

The sealed tray of the invention is produced from a cardboard blankcomprising a bottom surrounded by sides connected in pairs in thecorners by bellows in two portions. These bellows are folded back insidethe tray against one of the sides. The first portion of the bellows,adjacent to the side receiving said bellows, comprises a cut-out in itsupper portion. This cut-out allows the second portion of the bellows andthe side that receives it to come into direct contact at the time ofassembly.

The volume of the tray is maintained by applying glue to the internalsurfaces of the sides that receive the bellows. This application of glueis adapted to rigidly bond together one of the faces of the firstportion of the bellows in the lower zone of the corresponding side withthe other face of the second portion in the upper zone of this side, atthe same time avoiding or stopping the possibility of liquid rising bycapillary action.

This tray structure calls for glue to be applied in adapted zones ofonly one side of the cardboard blank, and thus allows relatively simpleautomatic assembly lines to be used.

In addition, gluing the folded-back bellows to the inside of the trayproduces rigid locking at the corners that prevents liquids from risingup by capillary action to the cut edges of the cardboard blank at theupper cut-out made in one of the portions of the bellows, or at theupper edge of the tray.

Glue can in fact be applied to the whole of the surface of the side thatreceives the bellows. In this case the whole surface of the portion ofthe bellows containing the upper cut-out is rigidly locked on thecorresponding side and the small amount of liquid likely to stagnate inthe bottom of the tray is unable to find any juxtaposition of wallswhich would allow it to rise by capillary action.

According to another embodiment, gluing is performed by applying twospots of glue. The first spot of glue is applied on the transition linebetween the two portions of the bellows pressed against their receivingside, and the second in the upper portion to ensure rigid locking of theportion of the bellows that does not have a cut-out. In this particularembodiment, the first glue spot blocks or stops any possible rising ofthe liquid by capillary action and prevents this liquid from reachingthe cut edges of the tray.

The tray structure of the present application with bellows folded backon the inside also gives an impeccable external appearance to thefinished product and allows advertising to be printed on a smooth, evensurface.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be better understood and other advantages andcharacteristics revealed from the following description of a number ofembodiments of the invention. These should be read in conjunction withthe accompanying drawings. In these drawings:

FIG. 1 shows a possible form of the cardboard blank from which theliquid-tight tray of the invention can be produced.

FIGS. 2, 3 and 4 are perspective views of a corner of the tray duringassembly.

FIG. 5 is a perspective view of the tray of the invention afterassembly.

FIG. 6 is an enlarged partial view of the cardboard blank of FIG. 1,showing in detail one of the corners thereof.

FIG. 7 shows another embodiment where all corners are glued by coveringthe entire glue application area.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 is a flat view of a cardboard blank that can be assembled to forma liquid-tight tray. This blank 1 comprises a rectangular bottom 2surrounded by two large sides 3, 4 and two small end sides 5 and 6, saidlarge sides and said end sides all being approximately the same height.Sides 3, 4, 5 and 6 are substantially trapezoidal in shape in order toprovide a truncated-pyramid shaped tray. As such, as shown in FIG. 6,the interior angle α of each of sides 3 and 6, e.g., is greater than90°. Said sides are connected in pairs by corner bellows 7 which areintended to provide sealing in at least the bottom of the tray andadapted to stop liquid rising by capillary action.

The four bellows 7 are identical and each comprises two portions 8 and 9of a generally triangular shape, separated by a median folding line 10.Since interior angle α of each of the adjacent sides 5, 6 is greaterthan 90°, and the bottom 2 is rectangular, as mentioned above, the sumof the adjacent interior angles β of each of the generally triangularportions 8, 9 is less than 90°, each angle β being less than 45°. Theseangle values ensure the aforementioned truncated-pyramid shape of thetray, enabling a plurality of trays to be conveniently stacked after thesides are erected and glued together, as explained below. Obviously, ifboth angles α were 90° and the sum of the interior angles β of portions8 and 9 were likewise 90°, the blank, when erected, would form agenerally parallelepipedic shape.

The first portion 8 of the bellows 7 is adjacent to the correspondingsmall side 5 or 6. It extends from bottom 2 to a height less than thatof adjacent side 5, 6, so as to form an opening or cut-out 11 in itsupper portion. As shown in FIG. 1, upper edge 12 of triangle 8 extendssubstantially perpendicular to the edge of the adjacent side, startingfrom half the height of this side. To retain satisfactory sealing in thebottom of the tray and allow automatic assembly, a minimum height ofapproximately 1 cm is retained for this portion 8 of the bellows.

The second portion 9 of bellows 7 is adjacent to the corresponding largeside 3, 4. It extends substantially over the entire height of said largeside. Its free corner 13, adjacent to cut-out 11 is truncated to avoidhaving to handle a piece of cardboard whose corners are too sharp.

The internal face, at least, of blank 1 has been treated so as to beimpermeable, thus removing or at least limiting the penetration ofmoisture originating from the packaged products into the heart of thecardboard.

The tray is assembled in automatic fashion by appropriate automaticmeans.

This assembly is effected by folding back portions 8 and 9 of bellows 7against the. internal faces of either small sides 5, 6 or large sides 3,4, depending on the case. This choice depends on the dimensions of thetray and according to the techniques used if it is covered withstretchable plastic film. In the present case, bellows 7 are folded backagainst the internal faces of small sides 5 and 6.

The presence of the bellows inside the tray makes for a qualityappearance, and does not interfere with stacking the products one insidethe other providing conicity is provided (to be determined according tothe final result required). It is also possible to print externalmarkings (advertizing, decoration, information, etc.) on a smooth, evensurface.

The first stage of the assembly consists in applying glue to the sidezones of the internal face of small sides 5 and 6 against which the twoportions 8 and 9 of the bellows will be pressed. The glue can be appliedeither over the whole of cross-hatched surface 14 shown in FIG. 7, or inthe form of carefully placed spots of glue as will be describedhereinafter.

As shown in FIGS. 2 to 4, the following stage consists in lifting upsides 3, 4, 5 and 6 and pressing the two portions 8 and 9 of cornerbellows 7 against the receiving side 5, 6. As a result of thisoperation, the front side of the first portion 8 of the bellows ispressed against the lower glue application zone. Moreover, thanks to thepresence of cut-out 11, the back side of second portion 9 of the bellowsis pressed against the upper glue application zone. By means of theconfiguration of the cut-out 11 and upper edge 12 of the first portion 8of the bellows 7, it can be seen particularly in FIG. 1 that asignificant portion of the surface area of the second portion 9 ofbellows 7, i.e., more than one-half, is available for being secured tothe adhesive or glue application zone 14. In addition, the free corner13 of the second portion 9 of the bellows extends beyond the upper edge12 of the first portion 8, the free corner 13 of the second portion 9thereby having an edge which forms an angle φ with edge 12, as shown inFIG. 6. Since the free corner 13 extends beyond the upper edge 12, asshown, the angle φ is less than 180°.

In a preferred embodiment shown in FIG. 1, the glue is applied in theform of two spots of glue 15 and 16, vertically aligned on glueapplication zone 14. Spot of glue 15 is placed at the level of upperedge 12 of first portion 8 of the bellows. It blocks the transition linebetween this first portion 8 and second portion 9 of the bellows.Moreover, it prevents moisture from rising by capillary action. Thesecond spot of glue 16 is placed in the upper portion. It rigidly locksthe internal face of small side 5, 6 against second portion 9 of thebellows. Depending on the height of the tray, additional spots of gluecan be added. Note also that glue can be applied by pad to obtain alarger gluing area.

Glue is applied to only one side of the blank, and is followed by a veryfast and simple assembly stage that can be carried out at very highspeed.

The specific assembly procedure results in correct locking at thecorners and good sealing of bellows at the bottom of the tray.

In a further embodiment, it is possible to remove the fold line providedbetween second portion 9 of the bellows and adjacent side 3, 4. Thisembodiment makes it possible to produce a tray with less sharp, slightlyrounded corners.

The truncated-pyramid shape of the tray, whereby the sides 3, 4, 5 and 6flare upwardly and outwardly from the bottom 2, facilitates the stackingof empty trays. This shape can of course be varied while retaining thesame structure and assembly principle.

Indeed, the sides of the tray can be perpendicular to the bottom, withangles α being 90°, so as to form a packaging tray in the form of aparallelepiped. Moreover the bottom 2 may have any polygonal form.

In addition, cut-out 11, made in the upper zone of one of the portionsof the bellows, can be made by any appropriate means and presented inany shape.

I claim:
 1. A fluid-tight, boat-shaped packaging tray, comprising:abottom comprising an internal face, surrounded by sides, each sidecomprising an internal face, connected in pairs by bellows; each of saidbellows comprising first and second portions, said second portion havinga predetermined surface area which is bordered by one of said sides andby said first portion of the bellows; said first portion of said bellowscomprising an upper, cut-out portion defined by an upper edge extendingfrom said second portion of said bellows to a respective adjacent one ofsaid sides; said bellows being folded inwardly and rigidly lockedagainst a corresponding internal face of a corresponding side by anadhesive located at and above said upper edge of said first portion ofsaid bellows, such that said bellows is capable of preventing orstopping liquid contained in said packaging tray from rising bycapillary action; and said upper edge of said first portion of saidbellows extending to said adjacent one of said sides at a position forenabling a majority of said predetermined surface area of said secondportion of said bellows to come into direct contact with the internalface of a corresponding side.
 2. The fluid-tight packaging tray of claim1, wherein said adhesive is disposed between an internal face of a sideof the packaging tray and said second portion of said bellows to affixsaid second portion to said side, and wherein said adhesive is alsodisposed between said side of said packaging tray and said upper edge ofsaid first portion of said bellows, so as to maintain said packagingtray in an assembled configuration.
 3. The fluid-tight packaging tray ofclaim 2, wherein said adhesive comprises a plurality of separate spots.4. The fluid-tight packaging tray of claim 1, wherein the second portioncomprises a substantially planar member consisting of two majorsurfaces, and wherein the predetermined surface area comprises an entiresurface area of one of the major surfaces.
 5. The fluid-tight packagingtray of claim 1, wherein substantially all of said upper portion of saidfirst portion is cut away.
 6. The fluid-tight packaging tray of claim 5,wherein said first portion of said bellows has a height of at least onecentimeter.
 7. The fluid-tight packaging tray of claim 1, wherein saidbellows extends over at least substantially one half of the height ofsaid sides.
 8. The fluid-tight packaging tray according to claim 1,wherein said bellows are folded back upon opposing sides of saidpackaging tray at the corners of the packaging tray.
 9. The fluid-tightpackaging tray of claim 1, wherein at least one of said internal facesof said bottom and sides is substantially fluid impermeable.
 10. Thefluid-tight packaging tray of claim 4, wherein said first and secondportions of said bellows are separated by a median fold line.
 11. Thefluid-tight packaging tray of claim 1, further comprising a generallyrectangular bottom, surrounded by four sides.
 12. The fluid-tightpackaging try of claim 11, comprising two large sides and two smallsides.
 13. The fluid-tight packaging tray of claim 1, wherein each ofsaid sides has a respective predetermined height, and wherein said upperedge of said first portion of said bellows extends to a position atsubstantially one-half of said predetermined height of said adjacent oneof said sides.
 14. The fluid-tight packaging tray of claim 1, whereinsaid upper edge of said first portion of said bellows extendssubstantially perpendicularly to an edge of an adjacent one of saidsides.
 15. The fluid-tight packaging tray of claim 1, wherein said upperedge of said first portion of said bellows has a predetermined lengthextending from an edge of said second portion of said bellows to an edgeof an adjacent one of said sides, and wherein said adhesive extendscompletely along and covers said predetermined length of said upper edgeof said first portion of said bellows.
 16. The fluid-tight packagingtray of claim 11, wherein said upper edge of said cut-out portion formsan angle of less than 180° with an edge of said second portion of saidbellows.
 17. The fluid-tight packaging tray of claim 1, wherein saidfirst and said second portions of said bellows are separated by a medianfold line along which said bellows are folded, said fold line forming,with an adjacent one of said sides, an interior angle, said interiorangles of both of said first portion and said second portion of each ofsaid bellows equalling a sum of less than 90°.
 18. The packaging tray ofclaim 1, wherein said sides flare upwardly and outwardly from saidbottom.
 19. The fluid-tight packaging tray of claim 1, wherein saidadhesive does not coat the entirety of said internal faces of saidbottom and said sides.
 20. A cardboard blank for producing a fluid-tightpackaging tray, said blank comprising:a bottom comprising an internalface, surrounded by sides, each side comprising an internal face,connected in pairs by bellows; each of said bellows being foldable tocontact a corresponding internal face of a respective one of said sidesat a bellows-receiving area and comprising first and second portions,said second portion having a predetermined surface area which isbordered by one of said sides and by said first portion of the bellows;said first portion of said bellows having an upper, cut-out portiondefined by an upper edge extending from said second portion of saidbellows to a respective adjacent one of said sides; said upper edge ofsaid first portion of said bellows extending to said adjacent one ofsaid sides at a position for enabling a majority of said predeterminedsurface area of said second portion of said bellows to come into directcontact with the internal face of a corresponding side, upon erectionand assembly of said blank to form said packaging tray; and an adhesiveon the internal face of only one side of each of said pairs of sides ofsaid blank at said bellows-receiving area and located at least at alocation corresponding to said upper edge of said first portion of saidbellows and above said location.
 21. The cardboard blank of claim 20,wherein said adhesive is in the form of a plurality of separate spots onthe internal face of said sides.
 22. The cardboard blank of claim 20,wherein substantially all of said upper portion of said first portion ofsaid bellows is cut away.
 23. The cardboard blank of claim 20, where insaid bellows extends over at least substantially one half of the heightof said sides, upon assembly and erection of said packaging tray. 24.The cardboard blank of claim 20, wherein the second portion comprises asubstantially planar member consisting of two major surfaces, andwherein the predetermined surface area comprises an entire surface areaof one of the major surfaces.
 25. The cardboard blank of claim 20,wherein each of said sides has a respective predetermined height, andwherein said upper edge of said first portion of said bellows extends toa position at substantially one-half of said predetermined height ofsaid adjacent one of said sides.
 26. The cardboard blank of claim 20,wherein said upper edge of said first portion of said bellows extendssubstantially perpendicularly to an edge of an adjacent one of saidsides.
 27. The cardboard blank of claim 20, wherein said adhesive doesnot coat the entirety of said internal faces of said bottom and saidsides.
 28. The cardboard blank of claim 20, wherein said upper edge ofsaid first portion of said bellows has a predetermined length extendingfrom an edge of said second portion of said bellows to an edge of anadjacent one of said sides, and wherein, upon said erection and assemblyof said blank to form said packaging tray, said adhesive extendscompletely along and covers said predetermined length of said upper edgeof said first portion of said bellows.
 29. The cardboard blank of claim20, wherein said upper edge of said cut-out portion forms an angle ofless than 180° with an edge of said second portion of said bellows. 30.The cardboard blank of claim 20, wherein said first and said secondportions of said bellows are separated by a median fold line along whichsaid bellows are folded, said fold line forming, with an adjacent one ofsaid sides, an interior angle, said interior angles of both of saidfirst portion and said second portion of each of said bellows equallinga sum of less than 90°.
 31. A process for manufacturing a fluid-tightpackaging tray from a cardboard blank, said cardboard blank comprising abottom comprising an internal face, surrounded by sides, the sidescomprising internal faces, connected in pairs by bellows, the bellowscomprising first and second portions, said second portion having apredetermined surface area which is bordered by one of said sides and bysaid first portion of the bellows, said first portion of said bellowscomprising a cut-out portion defined by an upper edge extending fromsaid second portion of said bellows to a respective adjacent one of saidsides, each of said bellows being foldable to contact a correspondinginternal face of a predetermined one of said sides at abellows-receiving area;the process comprising:a) applying an adhesive tosaid bellows-receiving area at least corresponding to and above saidupper edge of said first portion of said bellows; b) erecting the sidesof the packaging tray; and c) inwardly folding said first and secondportions of said bellows so as to contact said bellows-receiving area,to affix said first portion of said bellows and a majority of saidpredetermined surface area of said second portion of said bellowsthrough said cut-out portion to said bellows receiving area.
 32. Theprocess of claim 31, wherein step a) comprises applying a plurality ofspots of adhesive comprising applying at least one spot of said adhesivebetween a side of the packaging tray and said upper portion of saidsecond portion of said bellows, and at least one spot of adhesivebetween said side of said packaging tray and said upper edge of saidfirst portion of said bellows, so as to form a block between said firstand second portions of said bellows and to affix said second portion ofsaid bellows to said side.
 33. The process of claim 31, wherein thesecond portion comprises a substantially planar member consisting of twomajor surfaces, and wherein the predetermined surface area comprises anentire surface area of one of the major surfaces.
 34. The process ofclaim 31, wherein the adhesive of step a) is applied to only theinternal face of the sides of said blank.
 35. The process of claim 31,wherein the adhesive of step a) is applied to substantially the entirearea of said bellows-receiving area of said side of the packaging tray.36. The process of claim 31, wherein each of said sides has a respectivepredetermined height, and wherein said upper edge of said first portionof said bellows extends to a position at substantially one-half of theheight of said adjacent one of said sides.
 37. The process of claim 31,wherein said upper edge of said first portion of said bellows extendssubstantially perpendicularly to an edge of an adjacent one of saidsides.
 38. The process of claim 31, wherein said step of applying anadhesive consists of applying adhesive to only a pair of opposite sidesat respective ones of said bellows-receiving areas.
 39. The process ofclaim 31, wherein said upper edge of said first portion of said bellowshas a predetermined length extending from an edge of said second portionof said bellows to an edge of an adjacent one of said sides, andwherein, following said steps of applying an adhesive, erecting thesides, and inwardly folding said first and second portions of saidbellows, said adhesive extends completely along and covers saidpredetermined length of said upper edge of said first portion of saidbellows.
 40. The process of claim 31, wherein said upper edge of saidcut-out portion forms an angle of less than 180° with an edge of saidsecond portion of said bellows.
 41. The process of claim 31, whereinsaid step of inwardly folding said first and second portions of saidbellows comprises inwardly folding said first and said second portionsof said bellows along a median fold line, said fold line forming, withan adjacent one of said sides, an interior angle, said interior anglesof both of said first portion and said second portion of each of saidbellows equalling a sum of less than 90°.
 42. The process of claim 31,wherein said step of erecting the sides of the packaging tray compriseserecting the sides so that they are positioned to flare upwardly andoutwardly from the bottom.
 43. A packaging tray comprising:a bottomcomprising an internal face, surrounded by sides, each side comprisingan internal face, connected in pairs by bellows, each of said sideshaving a predetermined height, each of said bellows comprising first andsecond portions demarcated by a median fold line extending from a cornerof said bottom; said second portion having a predetermined surface areawhich is bordered by one of said sides and by said first portion of thebellows; said first portion of said bellows having an upper, cut-outportion defined by an upper edge extending at an angle from an edge ofsaid second portion of said bellows to a respective adjacent one of saidsides at a position at substantially one-half of the predeterminedheight of said one of said sides, said second portion of said bellowsthereby extending beyond said upper edge of said first portion of saidbellows; said bellows being folded inwardly along said median fold lineand being rigidly locked against a corresponding internal face of acorresponding side by an adhesive located at and above said upper edgeof said first portion of said bellows, such that said bellows is capableof preventing or stopping liquid contained in said packaging tray fromrising by capillary action to said upper edge of said first portion ofsaid bellows; and said cut-out portion of said first portion of saidbellows allowing at least part of said second portion of said bellows tocome into direct contact with the internal face of a corresponding side.44. The packaging tray of claim 43, wherein the second portion comprisesa substantially planar member consisting of two major surfaces, andwherein the predetermined surface area comprises an entire surface areaof one of the major surfaces.
 45. The packaging tray of claim 43,wherein said upper edge of said cut-out portion forms an angle of lessthan 180° with said edge of said second portion of said bellows.
 46. Thepackaging tray of claim 43, wherein said median fold line forms, with anadjacent one of said sides, an interior angle, said interior angles ofboth of said first portion and said second portion of each of saidbellows equalling a sum of less than 90°.
 47. The packaging tray ofclaim 43, wherein said sides flare upwardly and outwardly from saidbottom.
 48. A fluid-tight, boat-shaped packaging tray, comprising:abottom comprising an internal face, surrounded by first and secondsides, the first side being shorter than the second side, each sidecomprising an internal face, connected in pairs by bellows; each of saidbellows comprising first and second portions, said second portion havinga predetermined surface area which is bordered bv one of said sides andby said first portion of the bellows; said first portion of said bellowscomprising an upper, cut-out portion defined by an upper edge extendingfrom said second portion of said bellows to said first side; saidbellows being folded inwardly and rigidly locked against an internalface of said first side by an adhesive located at and above said upperedge of said first portion of said bellows, such that said bellows iscapable of preventing or stopping liquid contained in said packagingtray from rising by capillary action; said upper edge of said firstportion of said bellows extending to said first side at a position forenabling a majority of said predetermined surface area of said secondportion of said bellows to come into direct contact with the internalface of said first side; and said first and said second portions of saidbellows being separated by a median fold line along which said bellowsare folded, said fold line forming, with an adjacent one of said sides,an interior angle, said interior angles of both of said first portionand said second portion of each of said bellows equalling a sum of lessthan 90°, and each of said first and second sides being flared to forman angle between said bottom and said respective portions which isgreater than 90°.
 49. The fluid-tight, boat-shaped tray of claim 48,wherein the second portion comprises a substantially planar memberconsisting of two major surfaces, and wherein the predetermined surfacearea comprises an entire surface area of one of the major surfaces. 50.A process for manufacturing a fluid-tight packaging tray from acardboard blank, said cardboard blank comprising a bottom comprising aninternal face, surrounded by first and second sides, the first sidebeing shorter than the second side, each side comprising an internalface, connected in pairs by bellows, said second portion having apredetermined surface area which is bordered by one of said sides and bysaid first portion of the bellows, said first portion of said bellowscomprising an upper, cut-out portion defined by an upper edge extendingfrom said second portion of said bellows to said first side, said firstand said second portions of said bellows being separated by a medianfold line along which said bellows are folded, said fold line forming,with an adjacent one of said sides, an interior angle, said interiorangles of both of said first portion and said second portion of each ofsaid bellows equalling a sum of less than 90°, said first and secondsides being flared to form angles between said bottom and saidrespective portions which are greater than 90°, each of said bellowsbeing foldable to contact the first and second portions of said bellowswith the internal face of said first side at a bellows-receiving area,the process comprising:a) applying an adhesive to said bellows-receivingarea at least corresponding to and above said upper edge of said firstportion of said bellows; b) erecting the sides of the packaging tray;and c) inwardly folding said first and second portions of said bellowsso as to contact said bellows-receiving area, to affix said firstportion of said bellows and a majority of said predetermined surfacearea of said second portion of said bellows through said cut-out portionto said bellows receiving area.
 51. The process of claim 50, wherein thesecond portion comprises a substantially planar member consisting of twomajor surfaces, and wherein the predetermined surface area comprises anentire surface area of one of the major surfaces.